Currently used printers can be classified into various types according to the printing methods used. Among those printers, what is termed as an impact printer performs printing by pressing an ink ribbon impregnated with ink on a paper sheet, and thus by transferring the ink to the paper sheet. The impact printer is also used widely now to make prints on carbon or pressure-sensitive multi-sheet business forms particularly.
More specifically, in the impact printer, a part of the ink ribbon impregnated with ink is disposed so that a face of the ink ribbon can be parallel to the printing surface of the paper sheet. Moreover, pins are driven out of a print head disposed opposite to the paper so that the ink ribbon is interposed in between, and thereby make the ink ribbon collide with (impact on) the paper sheet. Accordingly, the ink is transferred to the paper sheet only at spots where the ink ribbon comes into contact with the paper sheet. Thus, the impact printer makes prints by repeating the above operation at high speed.
The ink ribbon is generally an endless ribbon having one end and the other end connected to each other, and most of the ribbon is stored in a cartridge main body. Moreover, parts of the ink ribbon required for printing, in other words, sufficiently impregnated with ink are sequentially drawn out (fed) from one end of the cartridge main body. Then, after being used for printing, those parts of the ink ribbon are sequentially re-stored into the cartridge main body from the other end of the cartridge main body.
In other words, a part of the entire ink ribbon having a certain length is always exposed to the outside of the cartridge main body. Moreover, as printing advances, the exposed part in the entire ink ribbon is sequentially shifted.
One place of the exposed part of the ink ribbon is engaged with a component called a ribbon guide so that the ink ribbon can slide through the ribbon guide. Specifically, the ribbon guide has a function to support the exposed part of the ink ribbon and to guide the movement of the ink ribbon after being drawn out and until being restored.
By fixing the ribbon guide to the print head in the printer or the like, the ribbon guide reciprocates with the reciprocating movement of the print head inside the printer or the like, while guiding the ink ribbon. During such reciprocation, a part of the ink ribbon (hereinafter referred to as a “printing part”) that is supported by the ribbon guide and is located close to the print head is brought into contact with the paper sheet by the print head. Thus, printing is performed.
The cartridge main body, the ribbon guide and the ink ribbon, which is set in the cartridge main body and has the ribbon guide engaged therewith, will be hereinafter collectively referred to as a “ribbon cartridge.”
FIGS. 1A and 1B show a conventional typical ribbon cartridge 100.
In a conventional impact printer, a cartridge main body 104 which stores therein most of an ink ribbon 102, and a ribbon guide 106 engaged with a drawn-out (exposed) part of the ink ribbon 102 are mounted separately from each other in the printer. For this reason, in loading or replacement of the ribbon cartridge, there are problems such as twisting of the ink ribbon (see FIG. 1A) and excessive drawing-out of the ink ribbon (see FIG. 1B).
In the case where the ribbon guide is mounted and printing is started while the ink ribbon is left twisted, a crucial problem for the printer occurs that “proper printing cannot be performed,” when the twisted portion comes to a printing part 108.
Moreover, in the case where the twisted portion is stored in the cartridge main body 104, ribbon feed may no longer be performed. This is because the twisted ink ribbon is so narrow that the ribbon enters a rotating part of a ribbon feed mechanism in the printer and gets jammed therein.
In either case, there arises a situation in which the ink ribbon has to be replaced together with the ribbon cartridge 100.
Moreover, when the ink ribbon is excessively drawn out from the cartridge main body, the drawn-out and exposed ink ribbon needs to be stored manually so as to set the ink ribbon to a proper length. In this event, the ink ribbon is likely to be twisted. Thus, the ribbon cartridge is more likely to be mounted on the printer while the ink ribbon is left twisted.
In order to deal with such problems, there is a ribbon cartridge product as described below.
FIG. 2 shows this product. In a ribbon cartridge 200 shown in FIG. 2, a cartridge main body 202 and a ribbon guide 204 are connected to each other by use of a plastic bellows 206. Then, an ink ribbon slides inside the bellows. Thus, the ink ribbon is never twisted.
However, the bellows requires an extra space in a horizontal direction. Thus, the cartridge main body has to be reduced in size, and accordingly an overall length of the ink ribbon has to be reduced. As a result, the life of the ribbon cartridge becomes shorter than that of a conventional product.
Moreover, since the ink ribbon slides inside the bellows, this product requires a greater force to feed the ink ribbon due to friction between the bellows and the ink ribbon than the conventional product. Furthermore, cost is increased for the bellows. Thus, this product is not a high-value product.
In Japanese Patent Application Laid-open Publication No. 2005-280212, the following invention related to a ribbon cartridge is described. Specifically, a cartridge main body and a ribbon guide are engaged with each other in a brand-new condition. Then, also when the cartridge main body and the ribbon guide are mounted on a printer, the ribbon guide is attached to a predetermined position in the printer while the cartridge main body and the ribbon guide are still engaged with each other. Thus, twisting of a ribbon is prevented.
In this method, the cartridge main body is subsequently detached from the ribbon guide and mounted on a predetermined position in the printer. Accordingly, the method described above is effective in mounting a brand-new ribbon cartridge. However, the method is not effective in the following case during use of the printer. For example, the ribbon guide is detached from a print head together with the ink ribbon due to paper sheet jam or the like, and then the ribbon guide is attached to the printer again.
In other words, once the ribbon cartridge is mounted on the printer, the cartridge main body and the ribbon guide are attached to the printer separately from each other. Thus, when the ribbon guide is afterward detached from the printer due to the paper sheet jam or the like, the ink ribbon is likely to be twisted. Thus, there still remains a problem that the ribbon guide is re-attached while the ink ribbon is left twisted.
As described above, the conventionally used ribbon cartridge always has the problem of the twisted ink ribbon. Accordingly, it is a current situation that an operator has to take measures with enough care so as not to cause twisting of the ink ribbon in manually attaching and detaching the ribbon guide and the like to and from the printer.